1. Field of the Invention
This invention relates in general to the field of rotating toys. More specifically it relates to the yo-yo.
2. Description of Prior Art
The term yo-yo was derived from the equivalent meaning of come-come in the native language of the Philippines where the toy is thought to have evolved from a weapon in ancient times. Stones with a groove around the periphery have been found in archaeological sites. It is believed that the groove was carved in order to secure a twine or a strip of leather to the stone. A warrior or hunter could throw the stone, quickly recover it and throw it again. Archaeologists have shown that over many years the groove had been made deeper, presumed at first to allow the twine to be all wound within the groove for the convenience of carrying it. The user would not have thrown it from the wound up condition to wound an animal or enemy because this would have resulted in primarily rotational speed of the stone instead of linear speed. The first to have carried a deep groove stone would have had to allow the stone to drop while holding on to the end of the twine to run it out. When the stone reached the end of the twine and rotated back up the twine, the come-come was discovered.
Charles Murray of the Philippine Islands was the first to loop a string around the axle to form a double twisted tether. He did this to avoid the hole drilled through the center of the axle which was commonly used to attach the tether. Murray was granted a patent in 1922. This was the first configuration that allowed the yo-yo to spin freely in the loop at the end of the tether. This free spinning at the end of the tether is referred to as sleeping and is used for performing many trick maneuvers. The yo-yo may be returned to the hand from the sleep condition by a slight jerk on the tether. The phenomenon that takes place here is that following the jerk, the tether becomes momentarily slack and allows the semi tight loop of the tether to wind up on the axle, increasing the frictional drag as more tether is wound around the axle. Pedro Flores, also of the Philippine Islands is given credit for developing and promoting the sleeping yo-yo.
There have been numerous efforts to improve yo-yo performance. A novelty search of prior art relating to the yo-yo discovered the following patents.
______________________________________ Classification Inventor ______________________________________ U.S. Pat. No. 1,419,402 6/1922 446/250 Mosher 1,864,318 6/1932 446/250 Powell 2,591,954 4/1952 446/250 Madsen 2,629,202 3/1953 446/250 Stivers et. al. 2,645,881 7/1953 446/250 Frangos 2,676,432 4/1954 446/250 Field 2,773,328 12/1956 446/250 Fraenkel et. al. 2,891,351 6/1959 446/250 Madaras 2,975,547 3/1961 446/250 Greve 3,081,578 3/1963 446/250 Mosher 3,175,326 3/1965 446/250 Isaacson 3,184,885 5/1965 446/250 Gibson 3,201,895 3/1962 446/250 Stivers 3,256,635 6/1966 446/250 Radovan 3,444,644 5/1969 446/251 Sayegh 3,805,443 4/1974 446/250 Duncan 4,130,962 12/1978 446/250 Ennis 4,207,701 6/1980 446/250 Kuhn 4,273,275 6/1981 224/101 Vadnais 4,290,225 9/1981 446/250 MacCarthy 4,318,243 3/1982 446/250 MacCarthy 4,332,102 6/1982 446/250 Caffrey 4,437,261 3/1984 446/250 MacCarthy 4,442,625 4/1984 446/250 MacCarthy 4,895,547 1/1980 446/250 Amaral 5,017,172 5/1991 446/250 Seifert 5,100,361 3/1992 446/250 Kuhn 5,127,868 7/1992 446/250 Smollar 5,254,027 10/1993 446/250 McAvoy 5,389,029 2/1995 446/250 McAvoy Foreign Patents 22,401 10/1903 England 446/251 Weisshappel 15,824 4/1904 Austria 446/251 Weisshappel 209,288 1/1924 Philippine 446/250 Murray Islands 504,033 4/1936 England 446/266 Beresford ______________________________________